Spring base chair



FIG. 1 is a perspective view of the spring base chair of my new design;

FIG. 2 is a front elevation of the spring base chair of FIG. 1;

FIGS. 3 and 4 respectively are lefthand and righthand side elevations of the spring base chair shown in FIG. 1;

FIG. 5 is a rear elevation view of the spring base chair of FIG. 1;

FIG. 6 is a plan view of the spring base chair of FIG. 1; and

FIG. 7 is an inverted plan view of the spring base chair of FIG. 1. 

The ornamental design for a spring base chair, substantially as shown. 